Hitchhiker's Guide to Openbsd

4.6.2 - Setting the Time Zone
Time in Unix is not a simple thing (or put another way, time in Unix is a really simple thing, human time is a politically 
manipulated mess). Time zone files help the system convert Unix time (the number of seconds past midnight GMT, Jan 
1, 1970) to human time, taking into account things like time zones, daylight savings time (DST), DST rule changes, etc. 
They also include the history of changes. 
Multiple time zone definition files will sometimes give the same current time, but may have different history. For 
example, EST5EDT and US/Michigan have the same time NOW, but back in 1975, the rules were different, so if you 
were doing math with dates and times that involved 1975, you would care about the differences. You should use the most 
specific and accurate timezone file you can for your region, rather than one that just gives the correct time at this 
moment. 
OpenBSD's installer will help you find an appropriate time zone file for you if you are not sure. Simply hit "
?
" at each 
prompt, and the installer will show you options. If the first level of answers doesn't suite you, pick a continent or country, 
and look at your options there: 
What timezone are you in? ('?' for list) [right/EST5EDT] ?
Africa/ Chile/ GB-Eire Israel NZ-CHAT UCT
America/ Cuba GMT Jamaica Navajo US/
Antarctica/ EET GMT+0 Japan PRC UTC
Arctic/ EST GMT-0 Kwajalein PST8PDT Universal
Asia/ EST5EDT GMT0 Libya Pacific/ W-SU
Atlantic/ Egypt Greenwich MET Poland WET
Australia/ Eire HST MST Portugal Zulu
Brazil/ Etc/ Hongkong MST7MDT ROC posix/
CET Europe/ Iceland Mexico/ ROK posixrules
CST6CDT Factory Indian/ Mideast/ Singapore right/
Canada/ GB Iran NZ Turkey
What timezone are you in? ('?' for list) [right/EST5EDT] US
What sub-timezone of 'US' are you in? ('?' for list) ?
Alaska Central Hawaii Mountain Samoa
Aleutian East-Indiana Indiana-Starke Pacific
Arizona Eastern Michigan Pacific-New
What sub-timezone of 'US' are you in? ('?' for list) Michigan
http://www.openbsd.org/faq/faq4.html (17 of 43)9/4/2011 10:01:58 AM

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4 - OpenBSD 4.9 Installation Guide
We've now set the time to "US/Michigan". This creates a symbolic link in 
/etc
pointing to the appropriate zoneinfo file 
in 
/usr/share/zoneinfo
, something like this: 
/etc/localtime -> /usr/share/zoneinfo/US/Michigan
Note the directory "
right/
", this directory includes leap second adjustments, but otherwise duplicates the standard 
zoneinfo choices. More 
here
. 
(back to where we might have been)